Vessels or drums are used commercially to store and dispense various substances. An opening is provided in the vessel or its lid to allow the vessel to be filled into and to dispense the contents of the vessel. The vessel opening is typically sealed with a removable bung or cap. The bung is typically threaded into the opening and forms a seal to prevent the contents from escaping from the vessel.
In order to provide an indication of prior access to the contents of a vessel, a tamper evident cover may be placed over the bung. Certain existing covers use tear strips which are positioned along a skirt portion of the cover in order to remove the cover. A locking ring mounted on the inner surface of the skirt, on or below the tear strip, is directed radially inwardly and engages the lip of the bung to prevent removal of the cover. When the tear strip is torn, the cover may be removed from the bung. A torn tear strip evidences prior removal of the cover and possible tampering with the contents of the vessel.